Semiconductor memory with data line capacitive coupling

ABSTRACT

A method of accessing a semiconductor memory includes operations as follows. A first voltage is received at a first data line, and a second voltage is received at a second data line, during a write operation of the semiconductor memory, in which the first voltage is lower than the second voltage, and a first coupling line is capacitively coupled with the first data line to lower the first voltage at the first data line in the write operation of the semiconductor memory.

REFERENCE TO RELATED APPLICATION

The present application is a divisional application of U.S. applicationSer. No. 13/918,787, filed Jun. 14, 2013, which is hereby incorporatedby reference in its entirety.

BACKGROUND

Static random access memory (SRAM) is a type of semiconductor memorywhich stores data in the form of bits. SRAM includes cells which aredisposed in an array. The SRAM cells include transistors coupled to bitlines and word lines. The bit lines and word lines are used to read datafrom and write data to the memory cell.

However, with the increasing down-scaling of integrated circuits, theoperation voltages of the integrated circuits are reduced, along withthe operation voltages of memories. Accordingly, read and write marginsof the SRAM cells, which are measures of how reliably the data of theSRAM cells can be read from and written into, are reduced. The reducedread and write margins may cause errors in the respective read and writeoperations.

BRIEF DESCRIPTION OF THE DRAWINGS

The disclosure can be more fully understood by reading the followingdetailed description of various embodiments, with reference to theaccompanying drawings as follows:

FIG. 1 is a schematic diagram of an SRAM cell circuit in accordance withsome embodiments of the present disclosure;

FIG. 2 is a top view of an SRAM in accordance with some embodiments ofthe present disclosure;

FIG. 3 is a top view of a portion associated with a memory cell of theSRAM in FIG. 2, in accordance with some embodiments of the presentdisclosure;

FIG. 4 is a schematic diagram illustrating in cross section anarrangement of connection levels related to the SRAM illustrativelyshown in FIG. 3, in accordance with some embodiments of the presentdisclosure;

FIG. 5 is a graph of waveforms illustrating a write operation of thememory cell in FIG. 3, in accordance with some embodiments of thepresent disclosure;

FIG. 6 is a flow chart of a method illustrating the write operation ofthe memory cell in FIG. 3, in accordance with some embodiments of thepresent disclosure;

FIG. 7 is a top view of a portion associated with a memory cell of theSRAM in FIG. 2, in accordance with further embodiments of the presentdisclosure;

FIG. 8 is a top view of a portion associated with a memory cell of theSRAM in FIG. 2, in accordance with some yet other embodiments of thepresent disclosure;

FIG. 9 is a top view of an SRAM in accordance with some furtherembodiments of the present disclosure;

FIG. 10 is a schematic diagram illustrating the conditions before and inthe write operation with respect to the voltage control circuit in FIG.9, in accordance with some embodiments of the present disclosure;

FIG. 11 is a schematic diagram of a portion associated with a memorycell in FIG. 2 and the voltage control circuit in FIG. 9, in accordancewith some embodiments of the present disclosure; and

FIG. 12 is a top view of an SRAM in accordance with some yet otherembodiments of the present disclosure.

DETAILED DESCRIPTION

In the following description, specific details are presented to providea thorough understanding of the embodiments of the present disclosure.Persons of ordinary skill in the art will recognize, however, that thepresent disclosure can be practiced without one or more of the specificdetails, or in combination with other components. Well-knownimplementations or operations are not shown or described in detail toavoid obscuring aspects of various embodiments of the presentdisclosure.

The terms used in this specification generally have their ordinarymeanings in the art and in the specific context where each term is used.The use of examples in this specification, including examples of anyterms discussed herein, is illustrative only, and in no way limits thescope and meaning of the disclosure or of any exemplified term.Likewise, the present disclosure is not limited to various embodimentsgiven in this specification.

Although the terms “first,” “second,” etc., may be used herein todescribe various elements, these elements should not be limited by theseterms. These terms are used to distinguish one element from another. Forexample, a first element could be termed a second element, and,similarly, a second element could be termed a first element, withoutdeparting from the scope of the embodiments. As used herein, the term“and/or” includes any and all combinations of one or more of theassociated listed items.

As used herein, the terms “comprising,” “including,” “having,”“containing,” “involving,” and the like are to be open-ended, i.e., tomean including but not limited to.

FIG. 1 is a schematic diagram of an SRAM cell circuit 100 in accordancewith some embodiments of the present disclosure. The SRAM cell circuit100 includes two pass-gate devices PG-1 and PG-2 and transistors PU-1,PD-1, PU-2 and PD-2. In some embodiments, PU-1 and PU-2 are p-type finfield-effect transistors (FinFETs), and PD-1, PD-2, PG-1 and PG-2 aren-type FinFETs.

PG-1 and PG-2 work with the corresponding word line WL and thecorresponding bit lines BL and BLB. The drain of PG-1 is coupled to thedata node N1, and the drain of PG-2 is coupled to the data node N2. Thesources of PG-1 and PG-2 are coupled to the bit lines BL and BLB,respectively. The gates of PG-1 and PG-2 are coupled to thecorresponding word line WL.

The drains of PU-1 and PD-1 are coupled together at the data node N1.The gates of PU-1 and PD-1 are coupled together to the data node N2. Thesource of PU-1 is coupled to a power supply line CVDD having a powersupply voltage. The source of PD-1 is coupled to a complementary powersupply line CVSS having a complementary power supply voltage. The drainsof PU-2 and PD-2 are coupled together at the data node N2. The gates ofPU-2 and PD-2 are coupled together to the data node N1. The source ofPU-2 is coupled to the power supply line CVDD. The source of PD-2 iscoupled to the complementary power supply line CVSS.

PU-1 and PD-1 operate together as a first inverter. PU-2 and PD-2operate together as a second inverter. The first and second invertersare cross-coupled and function as a data storage. A data bit with alogic state is reflected at the node N1, and the complement of the samedata bit is reflected at the node N2.

In a read operation of the SRAM cell circuit 100, PG-1 and PG-2 areturned on by the signal at the word line WL. When PG-1 and PG-2 areturned on, the data bit at the node N1 is transferred through PG-1 tothe bit line BL, and the data bit at the node N2 is transferred throughPG-2 to the bit line BLB.

In a write operation of the SRAM cell circuit 100, a value to be writtenis provided at the bit line BL, and the complement of the same value isprovided at the bit line BLB. When PG-1 and PG-2 are turned on by thesignal at the word line WL, the value is written into the data storage.

FIG. 2 is a top view of an SRAM 200 in accordance with some embodimentsof the present disclosure. The SRAM 200 is an illustrative portion of anentire semiconductor memory. Other portions of the semiconductor memoryare within the contemplated scope of the present disclosure.

As illustrated in FIG. 2, the SRAM 200 includes a plurality of memorycells 210 arranged in an array. Each of the memory cells 210 is labeled“cell” and includes the SRAM cell circuit 100 in FIG. 1. Each column ofthe memory cells 210 is associated with a pair of coupling lines CL anda pair of bit lines BL and BLB. Each row of the memory cells 210 isassociated with a corresponding word line WL.

In a write operation of the SRAM 200, one of the memory cells 210 isselected to be written into, and the corresponding word line WL isapplied with a logic high signal. The corresponding bit lines BL and BLBare configured to have values being written into the correspondingmemory cell 210. The word lines WL corresponding to the unselectedmemory cells 210 are applied with a logic low signal, and the unselectedmemory cells 210 retain their values. The coupling lines CL areconfigured to assist the write operation of the SRAM 200. The operationsof the coupling lines CL are described below.

FIG. 3 is a top view of a portion associated with a memory cell 210 ofthe SRAM 200 in accordance with some embodiments of the presentdisclosure. The configuration in FIG. 3 is illustrative. Otherconfigurations are within the contemplated scope of the presentdisclosure.

In the SRAM 200, the power supply line CVDD and the complementary powersupply lines CVSS1 and CVSS2 are coupled to the memory cell 210. Thepower supply line CVDD is configured to provide a power supply voltageVDD for the memory cell 210. The complementary power supply lines CVSS1and CVSS2 are each configured to provide a complementary power supplyvoltage VSS which, in some embodiments, is ground, for the memory cell210.

The coupling line CL1 is configured to capacitively couple the couplingline CL1 with the bit line BL. Explained in a different way, acapacitance C1 is formed between the coupling line CL1 and the bit lineBL. Similarly, the coupling line CL2 is configured to capacitivelycouple the coupling line CL2 with the bit line BLB. Explained in adifferent way, a capacitance C2 is formed between the coupling line CL2and the bit line BLB.

In some embodiments, the coupling line CL1 is configured to capacitivelycouple the coupling line CL1 with the power supply line CVDD, and acapacitance C3 is formed therebetween. Further, the coupling line CL2 isconfigured to capacitively couple the coupling line CL2 with the powersupply line CVDD, and a capacitance C4 is formed therebetween.

In some other embodiments, the coupling line CL1 is formed between thepower supply line CVDD and the bit line BL in a conductive layer, andthe coupling line CL2 is formed between the power supply line CVDD andthe bit line BLB in the same conductive layer.

For illustration, the coupling lines CL1 and CL2, the power supply lineCVDD, and the bit lines BL and BLB are formed in the first direction 252which, in some embodiments, is a column direction. The complementarypower supply lines CVSS1 and CVSS2 and the word line WL are formed inthe second direction 254 which, in some embodiments, is a row direction.

As illustratively shown in FIG. 3, the coupling lines CL1 and CL2 arenot coupled together. In some embodiments, the coupling lines CL1 andCL2 are coupled together outside the array of memory cells 210 in FIG.2. As a result, the coupling lines CL1 and CL2 are configured to receivea same voltage pulse signal. For example, the coupling lines CL1 and CL2commonly receive a signal which could be a falling pulse signal or arising pulse signal.

FIG. 4 is a schematic diagram illustrating in cross section anarrangement of connection levels related to the SRAM 200 illustrativelyshown in FIG. 3, in accordance with some embodiments of the presentdisclosure.

For illustration, the conductive layer M1 is formed upon the substrate402 by various ways, which, for simplicity, are not shown. Theconductive layer M2 is formed upon the conductive layer M1, and isconnected to the conductive layer M1 through the vias Via-1. Theconductive layer M3 is formed upon the conductive layer M2, and isconnected to the conductive layer M2 through the vias Via-2. Othersemiconductor structures or layers between any two of the substrate 402and the conductive layers M1, M2 and M3 are within the contemplatedscope of the present disclosure.

In some embodiments, the lines CL1, CL2, BL, BLB and CVDD in FIG. 3 areformed in the conductive layer M1 in FIG. 4. Further, the lines CVSS1,CVSS2 and WL in FIG. 3 are formed in the conductive layer M2 in FIG. 4.

FIG. 5 is a graph of waveforms illustrating a write operation of thememory cell 210 in FIG. 3, in accordance with some embodiments of thepresent disclosure. For illustration, VDD indicates a logic high value,and, in some embodiments, is the power supply voltage. Furthermore, VSSindicates a logic low value, and, in some embodiments, is ground.Moreover, the write operation of data “1” or “0” indicates writing thelogic high or low value, respectively, into the memory cell 210. Detailsof the waveforms in FIG. 5 are explained with reference to FIG. 6.

FIG. 6 is a flow chart of a method 600 illustrating the write operationof the memory cell 210 in FIG. 3, in accordance with some embodiments ofthe present disclosure. For illustration, the operation of writing data“1” into the node N1 (shown in FIG. 1) of the memory cell 210 in FIG. 3is described by the method 600 together with the waveforms in FIG. 5.

In operation 605, VDD is received at the coupling lines CL1 and CL2before the write operation. VDD is also received at the power supplyline CVDD. Operation 605 corresponds to a time t505 in FIG. 5.

In operation 610, VDD is received at the bit line BL, and VSS isreceived at the bit line BLB. Explained in a different way, the logichigh value indicating data “1” to be written to the node N1 is providedat the bit line BL, and the logic low value to be written to the node N2is provided at the bit line BLB. Operation 610 corresponds to a timet510 in FIG. 5.

In operation 615, the word line WL is applied with VDD. For simplicity,operation 615 also corresponds to time t510 in FIG. 5.

In operation 620, after VSS is received at the bit line BLB, a fallingpulse signal having a fast transition from VDD to VSS is applied to thecoupling line CL2. Moreover, VDD is maintained at the coupling line CL1.Operation 620 corresponds to time t515 in FIG. 5.

In operation 625, the coupling line CL2 is capacitively coupled with thebit line BLB in accordance with the falling pulse signal at the couplingline CL2. Explained in a different way, the capacitance C2 is formedbetween the coupling line CL2 and the bit line BLB. VSS at the bit lineBLB is therefore pulled down due to the capacitance C2. As a result, alevel lower than VSS is generated at the bit line BLB. In someembodiments, VSS is ground, and a negative voltage lower than ground isgenerated at the bit line BLB.

Additionally, the coupling line CL2 is also capacitively coupled withthe power supply line CVDD in accordance with the falling pulse signalat the coupling line CL2. Alternatively stated, the capacitance C4 isformed between the coupling line CL2 and the power supply line CVDD. VDDat the power supply line CVDD is therefore pulled down due to thecapacitance C4. As a result, a level lower than VDD is generated at thepower supply line CVDD. Operation 625 corresponds to a time t520 in FIG.5.

Referring to FIG. 1, FIG. 3 and FIG. 5, when the level lower than VSS isgenerated at the bit line BLB, the node N2 is pulled down below VSSthrough PG-2 in the write operation of the SRAM cell circuit 100. PU-1is therefore turned on more quickly by the signal at the node N2 that iscoupled to the gate of PU-1. Accordingly, the data at node N1 or thedrain of PU-1 is pulled to VDD at the source of PU-1 more quickly. Inother words, the data at the bit line BL is written into the datastorage node N1 more quickly, thus improving the speed of the writeoperation.

Moreover, when the level lower than VDD is generated at the power supplyline CVDD, the voltage difference between the gate and source of PU-1 orPU-2 becomes smaller. As a result, PU-1 or PU-2 is less turned on, andthe node N1 or N2 is less pulled by PU-1 or PU-2, respectively, to thevoltage at the power supply line CVDD. For illustration, in the writeoperation of the data “0” at the bit line BL, the node N1 is less pulledby PU-1. As a result, the data “0” at the bit line BL can be transferredmore quickly to the node N1, thus improving the speed of the writeoperation as well.

The operations in FIG. 5 and FIG. 6 that are related to the writeoperation of data “1” to node N1 are for illustrative purposes.Operations to write data “0” to node N1 correspond to the operations towrite data “1” to node N2, which can be appreciated based on the writeoperation of data “1” to node N1 and the symmetrical characteristic ofthe memory cell 100 in FIG. 1.

For example, in the operation of writing data “0” into node N1, VSS isreceived at the bit line BL, and VDD is received at the bit line BLB.After VSS is received at the bit line BL, a falling pulse signal havinga fast transition from VDD to VSS is received at the coupling line CL1.Moreover, VDD is maintained at the coupling line CL2. Furthermore, thecoupling line CL1 is capacitively coupled with the bit line BL inaccordance with the falling pulse signal at the coupling line CL1.Similarly, the capacitance C1 is formed between the coupling line CL1and the bit line BL. VSS at the bit line BL is therefore pulled down dueto the capacitance C1. As a result, a level lower than VSS is generatedat the bit line BL.

The coupling line CL1 is also capacitively coupled with the power supplyline CVDD in accordance with the falling pulse signal at the couplingline CL1. Alternatively stated, the capacitance C3 is formed between thecoupling line CL1 and the power supply line CVDD. VDD at the powersupply line CVDD is therefore pulled down due to the capacitance C3. Asa result, a level lower than VDD is generated at the power supply lineCVDD.

In some embodiments, the aforementioned pull-down of the power supplyline CVDD occurs when the power supply line CVDD is floated, because thepower supply line CVDD is easily pulled down while the power supply lineCVDD is floated.

FIG. 7 is a top view of a portion associated with a memory cell 210 ofthe SRAM 200 in FIG. 2, in accordance with further embodiments of thepresent disclosure.

Compared with the embodiments in FIG. 3, the coupling lines CL11 andCL22 correspond to the coupling lines CL1 and CL2, respectively. Thecoupling line CL11 is above the bit line BL, and the coupling line CL22is above the bit line BLB, however. In some embodiments, the couplingline CL11 fully covers the bit line BL, and the coupling line CL22 fullycovers the bit line BLB.

Effectively, the coupling line CL11 s configured to capacitively couplethe coupling line CL11 with the bit line BL, and a capacitance C11 isformed therebetween. Similarly, the coupling line CL22 s configured tocapacitively couple the coupling line CL22 with the bit line BLB, and acapacitance C22 is formed therebetween.

In some embodiments, the power supply line CVDD, the bit lines BL andBLB, and the complementary power supply lines CVSS1 and CVSS2 are formedin the first direction 252.

Referring to FIG. 4 and FIG. 7, in some embodiments, the word line WL isformed in the conductive layer M1. Furthermore, the power supply lineCVDD, the bit lines BL and BLB, and the complementary power supply linesCVSS1 and CVSS2 are formed in the conductive layer M2 upon theconductive layer M1. Moreover, the coupling lines CL11 and CL22 areformed in the conductive layer M3 upon the conductive layer M2.

The operation of the coupling line CL22 is similar to that of thecoupling line CL2 in FIG. 3. For example, in the write operation, thecoupling line CL22 capacitively couples the coupling line CL22 with thebit line BLB when the coupling line CL22 receives the voltage pulsesignal having a transition from a logic high value to a logic low value.As a result, the capacitance C22 is formed.

Similarly, the operation of the coupling line CL11 is similar to that ofthe coupling line CL1 in FIG. 3. For example, in the write operation,the coupling line CL11 capacitively couples the coupling line CL11 withthe bit line BL when the coupling line CL11 receives the voltage pulsesignal having a transition from a logic high value to a logic low value.As a result, the capacitance C11 is formed.

FIG. 8 is a top view of a portion associated with a memory cell 210 ofthe SRAM 200 in FIG. 2, in accordance with some yet other embodiments ofthe present disclosure. Compared with the embodiments in FIG. 7, acoupling line CL33 is formed above the power supply line CVDD. In someembodiments, the coupling line CL33 fully covers the power supply lineCVDD.

Effectively, the coupling line CL33 is configured to capacitively couplethe coupling line CL33 with the power supply line CVDD, and acapacitance C33 is formed therebetween.

In some embodiments, the coupling lines CL11, CL22 and CL33 are formedin the first direction 252.

Referring to FIG. 4 and FIG. 8, in some embodiments, the coupling lineCL33 is formed in the conductive layer M3 where the coupling lines CL11and CL22 are formed.

The operation of the coupling line CL33 is similar to that of thecoupling line CL1 or CL2 in FIG. 3. For example, in the write operation,the coupling line CL33 capacitively couples the coupling line CL33 withthe power supply line CVDD when the coupling line CL33 receives thevoltage pulse signal having a transition from a logic high value to alogic low value. As a result, the capacitance C33 is formed.

The coupling lines in FIG. 3, FIG. 7 and FIG. 8 are separatelyillustrated. Any combination of the coupling lines in FIG. 3, FIG. 7 andFIG. 8 is within the contemplated scope of the present disclosure.

FIG. 9 is a top view of an SRAM 300 in accordance with some furtherembodiments of the present disclosure. Compared with the SRAM 200 FIG.2, the SRAM 300 further includes a voltage control circuit 305. Thevoltage control circuit 305 is connected to the coupling lines CL. Thevoltage control circuit 305 is configured to selectively output avoltage pulse signal to the corresponding coupling line(s) CL. In someembodiments, the voltage pulse signal is a falling pulse signal having afast voltage transition from logic high to logic low. In otherembodiments, the voltage pulse signal is a rising pulse signal having afast voltage transition from logic low to logic high.

In further embodiments, the voltage control circuit 305 includes aselector (not labeled) or a multiplexer (not labeled). The selector ormultiplexer is configured to output the voltage pulse signal to at leastone of the coupling lines CL associated with each column of the memorycells 210. For illustration in FIG. 3 and FIG. 9, in some embodiments,the voltage control circuit 305 outputs the voltage pulse signal to thecoupling line CL1 or the coupling line CL2. In other embodiments, thevoltage control circuit 305 outputs the voltage pulse signal to both ofthe coupling lines CL1 and CL2.

FIG. 10 is a schematic diagram illustrating the conditions before and inthe write operation with respect to the voltage control circuit 305 inFIG. 9, in accordance with some embodiments of the present disclosure.

For illustration, the voltage control circuit 305 in FIG. 9 transmits afirst voltage signal having VDD on a logic high path, and transmits asecond voltage signal having VSS on a logic low path. The coupling lineCL1 is connected through a switch SW1 to the logic high path or thelogic low path. The coupling line CL2 is connected through a switch SW2to the logic high path or the logic low path.

Before the write operation, the switch SW1 connects the coupling lineCL1 with the logic high path, and the switch SW2 connects the couplingline CL2 with the logic high path. As a result, the coupling lines CL1and CL2 are pre-charged by the voltage control circuit 305 to have VDD.

For illustration in the write operation of data “1” to the node N1, theswitch SW2 switches to connect the coupling line CL2 with the logic lowpath. As a result, the coupling line CL2 has a fast voltage transitionfrom VDD to VSS. While the coupling line CL1 still has VDD, the couplingline CL2 is capacitively coupled with the bit line BLB and the powersupply line CVDD.

In contrast, for illustration in the write operation of data “0” to thenode N1, the switch SW1 switches to connect the coupling line CL1 withthe logic low path. As a result, the coupling line CL1 has a fastvoltage transition from VDD to VSS. While the coupling line CL2 stillhas VDD, the coupling line CL1 is capacitively coupled with the bit lineBLB and the power supply line CVDD.

FIG. 11 is a schematic diagram of a portion associated with a memorycell 210 and the voltage control circuit 305 in FIG. 9, in accordancewith some embodiments of the present disclosure.

For illustration, the voltage control circuit 305 in FIG. 9 includestransistors M1-M4. In some embodiments, the transistors M1 and M3 arePMOS transistors, and the transistors M2 and M4 are NMOS transistors.

The transistor M1 has a gate configured to receive a control signalENABLE-3, a source configured to receive VDD, and a drain coupled to thecoupling line CL1. In some embodiments, the control signal ENABLE-3 isVSS. The transistor M2 has a gate configured to receive a control signalENABLE-1, a drain coupled to the coupling line CL1, and a sourceconfigured to receive VSS. The transistor M3 has a gate configured toreceive the control signal ENABLE-3, a source configured to receive VDD,and a drain coupled to the coupling line CL2. The transistor M4 has agate configured to receive a control signal ENABLE-2, a drain coupled tothe coupling line CL2, and a source configured to receive VSS.

Various operations of the embodiments in FIG. 11 correspond to theoperations in FIG. 6, and further include operations corresponding tothe transistors M1-M4, which are illustrated below.

Before the write operation of the memory cell 210, the transistors M2 isturned off by the control signal ENABLE-1, and the transistors M4 isturned off by the control signal ENABLE-2. Furthermore, the transistorsM1 and M3 are turned on by the control signal ENABLE-3. As a result, VDDis transmitted from the voltage control circuit 305 to the couplinglines CL1 and CL2.

In the write operation of data “1” to the node N1, the transistor M2remains turned off, the transistors M1 and M3 are turned off by thecontrol signal ENABLE-3. Moreover, the transistor M4 is turned on by thecontrol signal ENABLE-2. As a result, the coupling line CL2 has a fastvoltage transition from VDD to VSS. The falling pulse signalcorresponding to the transition from VDD to VSS is therefore received atthe coupling line CL2.

In contrast, in the write operation of data “0” to the node N1, thetransistor M4 remains turned off, the transistors M1 and M3 are turnedoff by the control signal ENABLE-3. Moreover, the transistor M2 isturned on by the control signal ENABLE-1. As a result, the coupling lineCL1 has a fast voltage transition from VDD to VSS. The falling pulsesignal corresponding to the transition from VDD to VSS is thereforereceived at the coupling line CL1.

FIG. 12 is a top view of an SRAM 400 in accordance with some yet otherembodiments of the present disclosure. Compared with the SRAM 300 inFIG. 9, the SRAM 400 includes a plurality of voltage control units 405.Each voltage control unit 405 is coupled to the coupling lines CLassociated with one column of the memory cells 210. Moreover, eachvoltage control unit 405 is configured to output a voltage signal to oneof the coupling lines CL associated with one column of the memory cells210, in the write operation of a selected one of the memory cells 210.

In operation, compared with the SRAM 300 in FIG. 9, each voltage controlunits 405 individually outputs the voltage signal to at least one of thecoupling lines CL.

The semiconductor memory and method of accessing a semiconductor memorydisclosed herein enable the speed of write operation to be improved.

In this document, except for the term “capacitively coupled”, the term“coupled” may be termed as “electrically coupled”, and the term“connected” may be termed as “electrically connected”. “Coupled” and“connected” may also be used to indicate that two or more elementscooperate or interact with each other.

The above illustrations include exemplary operations, but the operationsare not necessarily performed in the order shown. Operations may beadded, replaced, changed order, and/or eliminated as appropriate, inaccordance with the spirit and scope of various embodiments of thepresent disclosure.

In some embodiments, a method of accessing a semiconductor memory isdisclosed in which a first voltage is received at a first data line, anda second voltage is received at a second data line, during a writeoperation of the semiconductor memory, in which the first voltage islower than the second voltage, and a first coupling line is capacitivelycoupled with the first data line to lower the first voltage at the firstdata line in the write operation of the semiconductor memory.

A method is also disclosed herein and includes operations as follows.Signals are transmitted through a pair of data lines to a plurality ofmemory cells in a write operation. A first coupling line is coupled withone of the data lines via a first capacitive element therebewteen. Asecond coupling line is coupled with another one of the data lines via asecond capacitive element therebewteen.

A method is also disclosed herein and includes operations as follows. Afirst voltage is transmitted to a first coupling line and a secondcoupling line before a write operation. A power supply line is coupledto a plurality of memory cells. Signals are transmitted through a pairof data lines to the memory cells in the write operation. The firstcoupling line is coupled with one of the data lines via a firstcapacitive element therebewteen. The second coupling line is coupledwith another one of the data lines via a second capacitive elementtherebewteen.

As is understood by one of ordinary skill in the art, the foregoingembodiments of the present disclosure are illustrative of the presentdisclosure rather than limiting of the present disclosure. It isintended to cover various modifications and similar arrangementsincluded within the spirit and scope of the appended claims, the scopeof which should be accorded with the broadest interpretation so as toencompass all such modifications and similar structures.

What is claimed is:
 1. A method of accessing a semiconductor memory,comprising: receiving a first voltage at a first data line, andreceiving a second voltage at a second data line, during a writeoperation of the semiconductor memory, wherein the first voltage islower than the second voltage; and capacitively coupling a firstcoupling line with the first data line to lower the first voltage at thefirst data line in the write operation of the semiconductor memory. 2.The method of claim 1, wherein the operation of capacitively couplingthe first coupling line with the first data line comprises: receiving afalling pulse signal at the first coupling line, such that the firstdata line is pulled down to receive a voltage lower than the firstvoltage.
 3. The method of claim 2, further comprising: receiving a highvoltage signal at the first coupling line, before the write operation ofthe semiconductor memory.
 4. The method of claim 1, further comprising:capacitively coupling a second coupling line with a power supply linewhich receives a power supply voltage, in the write operation of thesemiconductor memory.
 5. The method of claim 4, wherein the operation ofcapacitively coupling the second coupling line with the power supplyline comprises: receiving a falling pulse signal at the second couplingline, such that the power supply line is pulled down to receive avoltage lower than the power supply voltage.
 6. The method of claim 1,wherein the semiconductor memory further comprises a first transistorand a second transistor, the first transistor is electrically coupledbetween the second voltage and the first coupling line, the secondtransistor is electrically coupled between the first voltage and thefirst coupling line, the method further comprising: turning off thefirst transistor and turning on the second transistor in the writeoperation of the semiconductor memory, such that the first coupling linereceives a falling pulse signal.
 7. A method, comprising: transmitting aplurality of signals through a pair of data lines to a plurality ofmemory cells in a write operation; coupling a first coupling line withone of the data lines via a first capacitive element therebewteen; andcoupling a second coupling line with another one of the data lines via asecond capacitive element there between.
 8. The method of claim 7,wherein the memory cells are arranged in a first direction and a seconddirection perpendicular to the first direction, and the method furthercomprises: coupling a power supply line to the memory cells, wherein thefirst coupling line, the second coupling line, the power supply line,and the data lines are formed in the first direction.
 9. The method ofclaim 8, further comprising: coupling a third coupling line with thepower supply line.
 10. The method of claim 7, further comprising:selectively outputting, by a voltage control circuit, a voltage signalto at least one of the first coupling line and the second coupling lineduring the write operation.
 11. The method of claim 7, furthercomprising: outputting, by one of a plurality of voltage control units,a voltage signal to one of the first coupling line and the secondcoupling line during the write operation.
 12. The method of claim 7,further comprising: transmitting a first voltage to the first couplingline according to a first control signal before the write operation; andtransmitting the first voltage to the second coupling line according tothe first control signal before the write operation.
 13. The method ofclaim 12, further comprising: stop transmitting the first voltage to thefirst coupling line and the second transmitting line during the writeoperation.
 14. The method of claim 12, further comprising: transmittinga second voltage to one of the first coupling line and the secondcoupling line during the write operation, wherein the second voltage islower than the first voltage.
 15. The method of claim 7, furthercomprising: transmitting, by a first transistor, a first voltage to thefirst coupling line according to a first control signal; andtransmitting, by a second transistor, the first voltage to the secondcoupling line according to the first control signal.
 16. The method ofclaim 15, wherein the first voltage is transmitted before the writeoperation, and the method further comprises: turning off the firsttransistor and the second transistor by the first control signal duringthe write operation.
 17. The method of claim 15, further comprising:pulling one of the first coupling line and the second coupling line to asecond voltage during the write operation, wherein the second voltage islower than the first voltage.
 18. A method, comprising: transmitting afirst voltage to a first coupling line and a second coupling line beforea write operation; coupling a power supply line to a plurality of memorycells; transmitting a plurality of signals through a pair of data linesto the memory cells in the write operation; coupling the first couplingline with one of the data lines via a first capacitive elementtherebewteen; and coupling the second coupling line with another one ofthe data lines via a second capacitive element there between.
 19. Themethod of claim 18, further comprising: stop transmitting the firstvoltage to the first coupling line and the second coupling line duringthe write operation.
 20. The method of claim 18, further comprising:transmitting a second voltage to one of the first coupling line and thesecond coupling line during the write operation, wherein the secondvoltage is lower than the first voltage.